Method of drying gluten



June 16, 1959 D. B. MONTGOMERY Erm. 2,891,045

` METHOD oF uRYxNG-GLUTEN med Feb. 1e, 1957 ,www0/W4 -p Salar/ay nited States Patent 2,891,045 METHOD or DRYING GLUTEN' Duncan B. Montgomery, West Seneca, and James G.

VMo'ore, Buffalo, NX., assgnors to Blaw-Knox Compa'ny, Pittsburgh,` Pa., a corporation of DelawareA Application February 19, 1957, Serial No. 641,141

2 Claims. (Cl. 260--112) 72 75% `starch 7 -l3% protein 0.4- 0.7% ash with the remaining being moisture and small amounts of natural sugars, fats, enzymes and other organic components. For practical purposes the protein content may be considered gluten and While the gluten presentin the wheat llour is relatively `small compared to the amount of starch, it exerts a very pronounced inuence on the character of the products made from the our, as well as on the method of separation in relining the starch.

Gluten in its active or vitalized form is a tough, elastic substance, extremely sticky and gelatinous in nature, of a grayish color, which becomes brown and brittle on drying and is found in the our of wheat and other grains. Through the application of heat, either at relatively low temperatures for a prolonged period of time or` at relativelyhigh temperatures for a short period of time, the gluten becomes inactive or devitalized, losing its elasticity and` becoming water insoluble somewhat like a hard boiled egg.

` Since the demand for starch in various forms is extensive and since for most applications the removal of gluten is necessary in the preparation of the refined starch, extensive surveys have been made of the markets available for the most economic use of this by-product.

`Basically the major gluten markets today resolve themselves into two categories, either for active or vitalized gluten or inactive or devitalized gluten. Thelargest market for the active or vitalized gluten is as a protein additive forbreakfastcereals; in reincorporation into baking ours;`and in the manufacture of so-called gluten bread for diabetics. ',Ihere are other uses `for the active or vitalized `gluten'but they are minor as compared with the demand in the cereal and baking industries. The inactive or devitalized gluten today `is mostly used for the manufacture of monosodium glutamate. The active or vitalized gluten commands a much higher pricethanthe inactive or devitalized gluten and the present invention is concerned with the production of the active or vitalized gluten. i

` Starch and gluten are now separated by several processes, one being the so-called dough process herein illustrated, another being a so-called batter process wherein the starch and gluten are initially produced as a slurry, and a third being a caustic process where the gluten is dissolved and the dissolved gluten later precipitated as globules. The present invention is applicable to drying gluten produced by any of these methods. With any of 2,89`,4 Patented June 16, 1959 these methods the gluten is recovered as ygun'i gluten containing about 30-40% solids and 70-60% moisture. In this form it is an extremely gummy, almost liver-like,` sticky mass, extremely dii'cult to handle. Present processing methods for this material involve either atmospheric drum drying, which results in an inactive or devitalized product, or low temperature vacuum shelf drying and grinding', which results iii the active or vitalized product. p p

The principal object of the present invention is to produce a uniformly high quality spray dried activeer vitalized gluten in the form of discrete particles.

Another object is to produce such dried gluten with noV apparent denaturalization or degradation of the vitality, solubility or other quality of the gluten, the dried product` of the present invention being capable, on being wetted,

of going back to its mbbery lform with no apparent loss ing the gluten which are `recovered by the practice of the l of elasticity.

Another object of the invention is to produce a stable free-owing dispersion of gluten particles in water which can be easily pumped and sprayed in the form of very fine droplets from a nozzle without danger of the gluten particles adhering to one another or clotting to form pieces which will clog the nozzle and without danger of the gluten particles building up on the surfaces of the lines through which the aqueous dispersion is passed. This principal object is achieved by the introduction of ammonia into the aqueous gluten mixture prior to, during or subsequent to the nal dispersion step prior to spray drying. i

Another object is to produce such a dispersion which can be permitted to stand for a long period o-f time without evidence of settling, stratification, or agglomeration of the dispersed gluten particles.

Another object is to produce a high quality of active or vitalized gluten in controlled, uniform fine particle size.`

Another object is to spray dry at such low temperatures, for such short time and with such uniform particle size of the gluten to be `dried as to avoid degradation or devitalization of any substantial part of the product, par- Another object is to provide such a process which is not" particularly critical and which is continuousin operation and requires little supervision.

Another object is to provide such a process which is applicable to all conventional processes for producing starch and gluten.

. Other objects and advantages of the invention will be apparent from the following description and drawing in which the figure is a diagrammatic representation of ap? paratus for producing starch and vitalized or active gluten from wheat flour in accordance with the invention by a so-called dough process.

While the invention is also applicable where the starch t and gluten are initially produced as a slurry and also to the p rocess where the gluten is initially dissolved in true solution by caustic and the gluten later precipitated as globules, the accompanying drawing illustrates apparatus suitable for carrying out the invention wherein the starch and gluten are produced by the so-called dough process, that is, the wheat tlour is first made into dough from pieces of which the starch is washed, the solids constitutpresent invention.

A feed S of wheat llour and a feed 6 of water are introduced into the hopper 8 of a dough mixer '9 where the our and water are kneaded into a dough with about 40% of its weight of water. After standing for an hour or more to hydrate the gluten the dough is cut into large lumps. These are kneaded and llow, as indicated at 1t), into a washing tank 11. Wash water is introduced into the Washing tank 11 from pipe 12 and an agitator 13 is immersed in the washing tank` to break up the dough into relatively small pieces and to separate the starch "t-heree from. The ldischarge `from the Washing tank 11 is onto the head or elevated end of a conventional starch separation table 14 on which the starch settles to the bottom of the table from which it is removed at intervals. From the tailend of the starch separation table the wash water and small pieces of gum gluten are `discharged onto a Vibrating screen 15 through which the wash water passes into a vat or pan 16 from which it is withdrawn at 1S.

The gum lgluten in the .fonn of small, elastic, extremely sticky gelatinous pieces having a composition of approxi.

mately 3,040% solids and 70-.60% moisture, travels down the vibrating screen 1,5and passes from its tail end i througha line 1,9.

The important feature of the invention is the introduction of Water and ammonia to produce an ammoniated slurry so that the subsequent dispersion step is effective in bringing the gluten to the required small particle size for spray drying and in maintaining these particles in stable dispersion and free fromtendency to clot or form into strings until the ammonia and water are `driven off in the spray dryer and the gluten is reduced to a discrete dry powder. The water and ammonia are shown as introduced from a line 20, the quantity of Water beingsuch as to produce a water-gluten mixture in the order of from about 8-10% gluten Solids and the amountof ammonia being added being such as to adjust this mixture to about pH 9.5-ill. Since in commercial processing some starch adheres to the gluten particles, this concentration of gluten results in a higher concentration of total solids. However, so far as the` present invention is concerned, the essential factor is the concentration of gluten solids.

The ammoniated slurry is then passed into a disperser 21 which can be of any suitable form, suchas a'hydraulic shear disperser, colloid mill Vor agitator, to reduce the small pieces of gum @gluten to the required small particle size. During and following such reduction and dispersion the particles of gluten are prevented from adhering or clotting to one `another by the presence of the ammonia which insures that each particle remains independently in `dispersion in the water as long as the ammonja is present.

The ammoniated slurryor dispersion of 'gum gluten particles in water from the disperser 21l passes through a line 22leading to the inlet of a high pressure pump 2,3. The discharge conduit 24 from this pump, which could also include a heat exchanger 27, connects with the nozzle 25 of a horizontal spray dryer indicated generally at 26. The temperature of the slurry dischargedl from the nozzle 25 can be from room temperature to 120 F. The spray dryer comprises a horizontal shell 28 having all @Bd head `2.9 at its wetend adjacent Vthe nozzle 25 and an end head 30 at its opposite or dry end. Hot air or gas` at' a temperature of from about 400,-,500 F. is introduced through the end head29 from` an inlet 31 in surrounding relation to the `spray .32 from thenozzle 2S.

This temperature is reduced 'byi evaporation so that thev average spray chamber temperature, at the center of the shell 28, is from about l902l0 F. The moist air or gasescapes through an exhaust duct $3 in the end head 3l) at a temperature of from about 180-200 F. The water and ammoniaare rapidly levaporated from the droplets forming the `spray 52 and containing the dispersed particles of gluten. These particles dryas independent or discrete particlesrand settle to the bottom of the shell 4 screw 35. By reducing the gluten to a uniform particle size in 21 and preventing clotting of these particles by the presence of the ammonia, the product is of uniformly high quality. With too great a variation in the size of the particles of gum ygluten sprayed into the dryer, the small particles would burn and be devitalized if the dryer temperature were adjusted to the larger size gluten particles and if this temperature were adjusted to the smaller size gluten particles, the larger size particles would be sticky. i

While the temperature of the entering gas .andreventhe average temperatureof the spray chamber 28 is. high and Woll in excess of tho temperature natnoly about 1,40 F., at which devitalization of gum gluten takes place, the gluten particles are subjected to Athese temperatures only for a short length of time and only while they are still evaporating moisture lso that the gluten particles themselves never reach these high temperatures but; re-

28 where they are removed as la line grayish White'dry 70 powderwithout apparent loss of any vitality, solubility or quality? through on .outlet spout 34 by o Conveyor main at such low temperatures as to avoid'lde radation stream, this boit-,is boforo tho slotoorottioios ,o a dovitoiiziiis temperature and oooordisglytho overall ofthe gluten. In this connection `it befseen that drying tho gluten particles in a horizontal Spray dfyf; the gluten particles settle by gravity from therhot gas` footis one` of low toorofotoro drying.

As a specific example of spray drying an ammoniated slurry or dispersion of glutenthe concentration of the dispersion to the nozzle 25 was 9.2% 'gluten solids; the delivery pressure of the pump 23 was maintained between 4.200 to 4500 Psi-a tho average temperature. of, tint-sneu?.y chamber 28 was maintained I :tetit/,ejt-Qnv l6x5 to 199.? and tho dried elution was Producto 'as otvitelizsdgfayisli' white tine powder vhaving a moisture content Vof n.

and a bulk density of 42.5 pounds per cubic y From the foregoing it will berseen biyaddik am;A monia as a dispersing agent and reducing `the. glute tov-` uniform particle size the gluten can lbelproduced high quality vitalized or activeV spray dried pow r ,11i contrast to the laborious, slow andcostly low` tempera.,- ture vacuum shelf drying now employed. v` n We claim: n l. The method of producing dried vitalizedsolidsfifrorn gum gluten, which comprises combining water,famrriorliaf and particles of gum glutento provide an .f aqueous slurry having a pH in the order of '9.5" saldi ammonia acting to maintain saidiglutenparticles in dispersion and'free rfrom tendencyl to .clot and strings, propelling a moving stream of, 'gas4 capahl absorbing moisture, heatingsaid stream i y perature ofbetween about 400 to5 00 raying ypf lets of said ammoniated slurry ilto saidstrearn" of gas, and removing the gluten resulting from ,the i" tion of said droplets before thetemperatnre of er'glute'n fiISoS to tho tompofoturo at Wbiolll 'dovitttlizotioit takes p ooo- 2. The method set forth in claim l wherein saidstreamJ of ses is propelled horizontally no Wiier'ioiiitlioflronotal; of Said sloten from ,Said Stroom off gas'ihvfeavitr- AReferences Cited in the lc` of this patent OTHER Shewfelt `et al.: Canadian Chemistry and Process Industrios, July 194.4, pp- 502, 519. 

1. THE METHOD OF PRODUCING DRIED VITALIZED SOLIDS FROM GUM GLUTEN, WHICH COMPRISES COMBINING WATER, AMMONIA AND PARTICLES OF GUM GLUTEN TO PROVIDE AN AMMONIATED AQUEOUS SLURRY HAVING A PH IN THE ORDER OF 9.5-11, SAID AMMINIA ACTING TO MAINTAIN SAID GLUTTEN PARTICLES IN STABLE DISPERSION AND FREE FROM TENDENCY TO CLOT AND FORM INTO STRINGS, PROPELLING A MOVING STREAM OF GAS CAPABLE OF ABSORBONG MOISTURE, HEATING SAID STREAM, OF GAS TO A TEMPERATURE OF BETWEEN ABOUT 400*F., SPRAYING DROPLETS OF SAID AMMONIATED SLURRY INTO SAID STREAM OF HEATED GAS, AND REMOVING THE GLUTEN RESULTING FROM THE EVAPORATION OF SAID DROPLETS BEFORE THE TEMPERATURE OF THE GLUTEN RISES TO THE TEMPERATURE AT WHICH DEVITALIZATION TAKES PLACE. 